1. Field of the Invention
The present invention relates to connectors, more particularly to connectors with improved impedance between contacts thereof.
2. Description of Related Art
USB (Universal Serial Bus) 2.0 connectors are widely used in electronic device, such as computers, PDA, DVD et al. An USB 2.0 connector usually consists of an insulative housing, four contacts retained in the insulative housing and a metal shell covering the insulative housing. The insulative housing has a base and a tongue extending forwardly from a front side of the base. The base is formed with four passageways for retaining the four contacts. Each contact has a retaining portion retained in the passageways, a contact portion forwardly extending to the tongue from a front end of the retaining portion and a tail portion bending downwardly from a rear end of the retaining portion for electrically connecting with a circuit board. The metal shell covers the insulative housing and forms a receiving space with the tongue for receiving a corresponding plug.
The four contacts include a power contact for transmitting power to the electronic device, a pair of differential signal contacts for transmitting high frequency signals and a grounding contact for grounding purpose. All contact portions of the contacts in the USB 2.0 connector are averagely arranged in a row on one side of the tongue, and all tail portions of the contacts are averagely arranged in a row at a rear side of the insulative housing.
With a miniature development of the electronic device, connectors are combined with each other for decreasing areas they occupy. The USB 2.0 connector is also combined with another connector, such as a power connector, an optical module et al to decreasing areas of the electronic device. The insulative housing would define a cavity at a middle and lower side thereof to retain the another connector. The another connector backwardly extends out of a rear side of the insultive housing. Then the tail portions of the USB 2.0 connector need to bend sidewardly and form a space therebetween for receiving a rear side of the another connector, and assembling the another connector from a rear side of the insulative housing convenienly. However, when a distance between the pair of differential signal contacts is increased, an electric capacity between the differential signal contacts would be reduced at the same time, which make an impedance between the differential signal contacts becomes higher, and result in distortion of signal transmission.
Hence, an improved connector is desired to overcome the above problems.